How we calculate the numbers in our travel calculators
By the Hotella editors · Updated
The calculators use simple formulas you can check yourself: the nightly rate is multiplied by nights and rooms, while breakfast and city tax are counted per person per night. There are no hidden mark-ups, and every default value can be changed.
The formulas
- Budget per night: (total budget − travel − food) ÷ nights, with a 10% buffer as the recommended maximum.
- Total cost: nightly rate × nights × rooms + breakfast × guests × nights + city tax × guests × nights + transport.
- Hotel vs. apartment: hotel = nightly rate × rooms × nights + breakfast × guests × nights. Apartment = nightly rate × nights + cleaning fee + groceries × nights.
The 10% buffer
The budget calculator recommends spending only 90% of your theoretical ceiling per night. The last 10% covers city tax, resort fees, card charges abroad and the extras that are only settled at the property.
City tax and fees
City tax is charged per person per night in most European and many North American destinations. It is rarely included in the rates listed by booking sites, because the property collects it on arrival — so the total cost calculator asks for it separately.
What we leave out
The hotel versus apartment comparison excludes transport, because it depends entirely on where each option sits. If the apartment is outside the centre, add the travel cost in the total cost calculator instead. We also ignore travel insurance, parking, cancellation fees and exchange-rate movement.
Currency and privacy
All amounts follow the currency you pick in the header, and nothing is converted between currencies. Every calculation runs in your browser: we do not send, log or store the numbers you type, and no prices are saved.
Frequently asked questions
- Which currency do the calculators use?
- They use whichever currency you have selected in the header. Amounts you type are treated as being in that currency, and the results are shown in the same one — we do not convert between currencies.
- Is city tax included in the price I see in search?
- Usually not. City tax is normally collected by the property on arrival, which is why the total cost calculator has a separate field for it.
- Where do the default values come from?
- They are rounded figures based on the price levels we see in our live searches for major European and North American cities in 2026. Every field can be overwritten.